import java.util.Scanner;

/**
 * Created with longelliJ IDEA.
 * Description:
 * User: ws
 * Date: 2022-12-20
 * Time: 22:13
 */
//https://www.acwing.com/problem/content/description/4405/
public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        //long确保数据在规定的范围内
        long a = scan.nextLong();
        long b = scan.nextLong();
        long n = scan.nextLong();
        long s = 5 * a + 2 * b;
        //将满足1周的化为天数
        long res = n / s * 7;
        //剩余不满足一周的
        n %= s;
        //将一周的天数存入数组，便于加减
        long[] arr = {a, a, a, a, a, b, b};
        //若n大于等于0则证明，该天的题数已经大于题数
        for (int i = 0; n > 0; i++) {
            n -= arr[i];
            //天数加一
            res++;
        }
        System.out.println(res);
    }
}
